高效液相色谱-串联质谱法测定芽苗类蔬菜及其来源豆类中4种非法添加物的残留量

建立了芽苗类蔬菜及其来源豆类中对氯苯氧乙酸、6-苄基腺嘌呤、恩诺沙星和诺氟沙星残留量的反相高效液相色谱-串联质谱(LC-MS/MS)检测方法。样品经含0.1%冰醋酸的乙腈提取、浓缩后,以C18为分析色谱柱,甲醇和0.1%甲酸水溶液作为流动相进行梯度洗脱分离。质谱采用电喷雾方式电离,正、负离子分段扫描,测定上述4种非法添加物。选择确定对氯苯氧乙酸、6-苄基腺嘌呤、恩诺沙星和诺氟沙星的母离子依次为m/z 189.9、226.1、359.9和320.1,定量子离子依次为m/z 127.0、91.2、315.9和276.2。4种药物在5～200 μg/L范围内线性关系良好(r2＞ 0.995)。选取了绿豆芽和绿豆作为代表性基质进行添加回收试验,4种药物的检出限和定量限分别为1 μg/kg和5 μg/kg;在5.0、10.0、20.0 μg/kg 3个添加水平下,4种药物的回收率为70%～91%,相对标准偏差(RSD)小于14%。方法准确、灵敏、简便,适用于芽苗类蔬菜及其来源豆类中4种非法添加物残留的同时测定。

Determination of four kinds of illegal additive residues in sprouts and source beans by high performance liquid chromatography-tandem mass spectrometry

A reversed-phase high performance liquid chromatography coupled with tandem mass spectrometric (LC-MS/MS) method was developed for the determination of 4-chlorophenoxyacetic acid, 6-benzylaminopurine, enrofloxacin and norfloxacin residues in sprouts and source beans. The sample was extracted by acetonitrile containing 0.1% acetic acid and concentrated. The chromatographic analysis was carried out on a C18 column with methanol and 0.1% formic acid solution as the mobile phases in gradient elution program. The MS analysis was set in electrospray ionization mode and separated to two segments of positive and negative modes. The precursor ions were m/z 189.9, 226.1, 359.9 and 320.1, while the product ions for quantification were m/z 127.0, 91.2, 315.9 and 276.2 for 4-chlorophenoxyacetic acid, 6-benzylaminopurine, enrofloxacin and norfloxacin, respectively. The calibration curves showed good linearity in the range of 5-200 μg/L with correlation coefficients more than 0.995. The limits of detection (LODs) were 1 μg/kg and the limits of quantification (LOQs) were 5 μg/kg for the four compounds spiked in mung bean sprouts and mung beans. The recoveries of the four compounds spiked at three levels of 5.0, 10.0 and 20.0 μg/kg ranged from 70% to 91%, with the relative standard deviations (RSDs) less than 14%. The method established is accurate, sensitive, simple, and has considerable advantages in the analysis of the four kinds of illegal additive residues in sprouts and beans simultaneously.